An individual owner can do whatever he wants to control his own salaries.

He can make the decision (like Burke has) that he won't sign these sorts of deals. He can make a decision to not give anyone a contract above $4 million / year or longer than 5 years.

There is absolutely nothing illegal or collusive about that.

Collusion comes in when a group of owners get together and say "Ok, none of us offer Crosby more than $5 million a year, that way he'll be forced to sign for that much"

Collusion, by definition, cannot apply to only 1 owners. It must apply to a group of owners working in concert

NHL owners absolutely could keep salary down if each of them individually made a decision not to try and break the bank on every contract. Instead they choose to engage in a bidding war.

Sure, A GM could make those decisions. And those decisions would result in that team losing all their star players to teams that can afford to pay players over $4 million. It would result in that GM's and Owner's team never making the playoffs losing fans and revenue. And unfortunately, most. Teams aren't like the Leafs that have a rabid fanbase regardless of the quality of the product on the ice. To expect owners to not engage in a bidding war, without some sort of agreement is completely unrealistic. There are teams that can afford those high salaries and it would be a disservice to that teams fans for those teams to not do whatever they can to better their team. Problem being, the teams that can afford it don't just raise prices for the rich teams, they raise them for everyone.